This work investigated the effect of temperature on corrosion of C38 steel in a hydrochloric medium (1M) in the absence and presence of the ethanolic extract from Eriobotrya Japonica (ERJ) seeds treated by maceration. For a better understanding of the corrosion process, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques had applied by increasing the temperature from 303.15 K to 333.15 K. Moreover, studying adsorption isotherms and determining thermodynamic parameters to understand the mechanism adopted in the adsorption of ERJ molecules on the metal surface. The results reveal that the inhibition efficiency increases with higher inhibitor concentration and decreases slightly with increasing temperature. Thus, the Langmuir model is the best model to fit the data obtained, and the adsorption follows a spontaneous physisorption process. According to the evolution of enthalpy, entropy, and activation energy, the inhibition capacity decreases is associated with a slow endothermic dissolution due to forming an active complex on the surface of C38.